Severe acute respiratory syndrome (SARS) is a recently recognized, highly infectious and life-threatening condition. (Lee N, et al., N. Engl. J. Med. 2003 May 15;348(20):1986-94; Poutanen S M, et al., N. Engl. J. Med. 2003 May 15;348(20):1995-2005; Tsang K W, et al., N. Engl. J. Med. 2003 May 15;348(20):1977-85). The World Health Organization issued a global alert on the condition on Mar. 12, 2003. Numerous cases have since been reported in many parts of the world affecting both health care workers and community citizens. Recent data have provided strong evidence that a novel coronavirus is likely to be an etiological agent for SARS. (Ksiazek T G, et al., N. Engl. J. Med. 2003 May 15; 348(20): 1953-66; Peiris J, et al., Lancet 2003;361:1319-25; Drosten C, et al., N. Engl. J. Med. 2003 May 15;348(20):1967-76). Thus far, little is known about the biology of this SARS-coronavirus (SARS CoV).
The SARS-CoV genome contains 11 open reading frames coding for a replicase, four major structural proteins: spike, nucleocapsid, envelope and membrane, and several proteins of unknown function. Spike protein is a membrane-bound glycoprotein located on the surface of the virion. This glycoprotein is reported to be important for viral entry and may define host range and tissue tropism (Gallagher T M and Buchmeier M J. (2001) Virology 279:371-374; Philips J J et al. (2002) Virology 301:109-120). Mutations of the spike glycoprotein gene of other coronaviruses have been correlated with altered pathogenesis and virulence (Bernard S and Laude H. (1995) J Gen Virol 76 (Pt 9):2235-2241; Leparc-Goffart I et al. (1997) Virology 239:1-10; Phillips J J; and Weiss S R. (2001) Adv Exp Med Biol 494:115-119).